Thin film transistor array substrate and electronic ink display device

Abstract

A thin film transistor (TFT) array substrate including a substrate, multiple scan lines, multiple data lines and multiple pixel units is provided. Each pixel unit includes a TFT and a pixel electrode. The pixel electrode is disposed above the TFT and electrically connected thereto. The TFT includes a first gate electrode, a first insulating layer, a semiconductor layer, a source electrode, a drain electrode, a second insulating layer and at least one second gate electrode. The second gate electrode is disposed on the second insulating layer positioned above the semiconductor layer and is electrically connected to the first gate electrode. The second gate electrode can be used to reduce the current leakage through the TFT. Moreover, an electronic ink display device comprising the above TFT array substrate is provided.

1 . A thin film transistor array substrate, comprising:
 a substrate;   a plurality of scan lines and a plurality of data lines disposed on the substrate;   a plurality of pixels, each of the pixels being electrically connected to one of the scan lines and one of the data lines, each of the pixels comprising a thin film transistor and a pixel electrode electrically connected to the thin film transistor, the pixel electrode being positioned above the thin film transistor, wherein the thin film transistor comprises:   a first gate electrode electrically connected to its respective scan line;   a first insulating layer overlaid on the first gate electrode;   a semiconductor layer disposed on the first insulating layer positioned above the first gate electrode;   a source electrode and a drain electrode disposed on the semiconductor layer and partially overlaid on the semiconductor layer, the source electrode being electrically connected to the respective data line, the drain electrode being electrically connected to the respective pixel electrode;   a second insulating layer overlaid on the source electrode, the drain electrode and the semiconductor layer; and   at least one second gate electrode disposed on the second insulating layer positioned above the semiconductor layer and electrically connected to the first gate electrode.   
   
   
       2 . The thin film transistor array substrate of  claim 1 , wherein the first insulating layer and the second insulating layer have an opening to expose part of the first gate electrode, thereby, the second gate electrode and the first gate electrode are electrically connected through the opening. 
   
   
       3 . The thin film transistor array substrate of  claim 1 , further comprising a plurality of common wires disposed on the substrate, the common wires being parallel to the scan lines and placed between the adjacent scan lines. 
   
   
       4 . The thin film transistor array substrate of  claim 1 , wherein the pixel electrode comprises a material selected from a group consisting of indium tin oxide, indium zinc oxide, metal and a combination thereof. 
   
   
       5 . An electronic ink display device, comprising:
 a thin film transistor array substrate of  claim 1 ; and   a front panel, disposed on one side of the thin film transistor array substrate, the front panel comprising:   a cover;   a transparent electrode layer disposed under the cover; and   an electronic ink layer, sandwiched in between the transparent electrode layer and the thin film transistor array substrate.   
   
   
       6 . The electronic ink display device of  claim 5 , wherein the first insulating layer and the second insulating layer have an opening to expose part of the first gate electrode, thereby, the second gate electrode and the first gate electrode are electrically connected through the opening. 
   
   
       7 . The electronic ink display device of  claim 5 , further comprising a plurality of common wires disposed on the substrate, the common wires being parallel to the scan line and placed between the adjacent scan lines. 
   
   
       8 . The electronic ink display device of  claim 5 , wherein the pixel electrode comprises a material selected from a group consisting of indium tin oxide, indium zinc oxide, metal and a combination thereof. 
   
   
       9 . The electronic ink display device of  claim 5 , wherein the electronic ink layer comprises a plurality of electronic ink particles and a transparent fluid. 
   
   
       10 . The electronic ink display device of  claim 9 , wherein the electronic ink particles comprises a plurality of dark particles and a plurality of bright particles, the dark particles and the bright particles are distributed over the transparent fluid, the dark particles and the bright particles have opposite polarity. 
   
   
       11 . The electronic ink display device of  claim 10 , further comprising a plurality of microcapsules, the dark particles, the bright particles and the transparent fluid being packaged in the microcapsules. 
   
   
       12 . The electronic ink display device of  claim 10 , further comprising a plurality of microcups, the dark particles, the bright particles and the transparent fluid being placed in the microcups. 
   
   
       13 . The electronic ink display device of  claim 5 , wherein the electronic ink layer comprises a plurality of electronic ink particles, each of the electronic ink particles has a bright color on one half of the electronic ink particles and a dark color on the other half of the electronic ink particles, each side of the electronic ink particles has opposite polarity.